Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Income tax provision	$ 28,727	$ 25,203	$ 48,952	$ 51,430
Effective income tax rates	37.80%	37.60%	37.80%	37.60%
Actual income tax rates	38.00%	37.70%	37.90%	37.70%
Unrecognized income tax benefits	$ 5,200		$ 5,200		$ 5,200
Unrecognized income tax benefits, if recognized, that would favorably affect the effective income tax rate	3,000		3,000		3,000
Accrued interest expense related to unrecognized income tax benefits	400		400		$ 300
Interest expense related to unrecognized income tax benefits	100	$ 100	100
Interest income related to unrecognized income tax benefits				$ 100
Unrecognized income tax benefits to be recognized in the next twelve months	$ 3,300		$ 3,300